With prior art telephone apparatus, abbreviated dialing functions or redial functions were obtained by using function keys (SEND, RECALL, STORE, etc.) in combination with the numeric or digit keys (0-9), or by using combinations of the special keys (*, #) in combination with the numeric keys. As used herein, "function keys" refers to all keys other than numeric and special keys. Other telephone number recall devices have used a plurality of function keys alone for retrieval of stored telephone numbers or have required activation of a SEND key in order to dial a previously stored telephone number. Such techniques require the handset to include additional keys, as well as require the user to remember and implement the specific sequence of operations to carry out the abbreviated dialing function.
In accordance with these prior art telephone systems, function keys can be used to store in memory the data which has been entered into the memory buffer. For instance, when a number has been entered into a memory buffer, it can be stored at a particular memory address location by pressing the STORE function key and then entering the memory address on the keypad. Numbers entered in a memory buffer through use of the digit keys can then be sent to the dialer by pressing the SEND function key. Numbers can also be recalled and dialed from memory by pressing the RECALL key and then entering an address location on the keypad and then pressing the SEND function key. There are additional functions which can be executed by the controller, depending upon the function key or sequence of function keys pressed. Thus, when a calling party wishes to dial a number stored in the memory, prior art telephone systems would typically require that the calling party actuate a plurality of function keys, such as a RECALL key, one or several address KEYS and a SEND key, in order to dial the number stored in the memory. Other prior art telephone systems require that the calling party actuate one of a plurality of non-keypad keys which consolidate the RECALL, address and SEND functions into a single key.
With the foregoing in mind, it is an object of the invention to provide the ability to recall and dial previously stored telephone numbers or billing account numbers from memory by actuation of a single standard keypad key, thereby obviating the need for additional function keys or multiple step key activation. It is further desirable to provide a telephone number recall feature which does not reduce the number of functions performed by a standard keypad. Another objective of the present invention is to provide for one-touch dialing of telephone numbers which can be used on telephone systems which accumulate numbers before dialing, as well as on telephone systems which do not accumulate or collect numbers but instead dial entered numbers directly. A still further objective of the present invention is to provide for increased functionality of a standard 12-key keypad without increasing the number of keys--an objective which is important in certain devices such as cellular telephones and cordless telephones wherein the number of keys is limited by the minimum physical size requirements for the keys.